Nutritional Assessment/Requirements Flashcards
Initial Pathway Steps
- Admission: Get height, weight, BMI
- Nutrition Screen within 24 hours
- Suspected Malnutrition?
Yes => Nutrition Assessment
No => Reassess in 3-7 days
Nutritionally-at-risk Factors
- Involuntary loss of >= 10% body weight within 6 months
- Involuntary loss of >=5% of usual body weight in 1 month
- Involuntary loss or gain of 10 lbs within 6 months
- BMI <18.5 or >25
- Chronic Disease
- Increased metabolic requirements
- Altered diets or diet schedules
- Inadequate nutrition intake, including no food or nutritional products for > 7 days
Assessment of Nutritional Status
- History and clinical diagnosis
- Physical exam/clinical signs
- Anthropometric data
- Labs
- Food/nutrition intake (history, calorie counts, diet, etc.)
- Functional assessment
Exam/Clinical Signs Gathered
Exams
- Weight loss/gain
- Fluid Retention
- Loss of muscle/fat
Clinical Signs
-Inflammation: fever/hypothermia, tachycardia, hyperglycemia
Anthropometric Data
- Weight: unintended weight loss if a validated indicator of malnutrition (measure at admission and repeat frequently)
- Height
- BMI: malnutrition can occur at any BMI
Weight Alone Problems
- Doesn’t provide body composition information
- Loss of serum proteins associated with ECF expansion
- Concomitant diseases (CHF, ARF, Cirrhosis) associated with increased ECF
Labs
- Markers of inflammation: elevated CRP, WBC, blood glucose levels
- Negative nitrogen balance: sometimes support systemic inflammatory response (nitrogen from urine over 24 hours)
Protein and Nitrogen Balance
- Nitrogen is a component of all amino acids
- Nitrogen Balance (NB) is difference between dietary nitrogen intake and nitrogen losses
- NB is a good marker for adequate protein intake
- Little evidence for using NB
NB
- NB = total protein intake (g)/6.25 - (UNN+4)
- Positive NB: patient excretes less N than they consume (using N in new proteins)
- Negative NB: excretes more N than they consume (use muscle as energy source)
- May be useful to know but not common in practice
Food/Nutrition Intake
-Get information from patient or caregiver
Methods to help determine inadequate intake:
- 24 hour recall
- Modified diet history
- Calorie count
- Prior documentation of periods of inadequate food intake in medical record
Functional Assessment
- Handgrip strength: documents decline in physical function
- Don’t use in ICU patients
Short Term “Simple” Undernutrition
- < 72 hours
- Glycogen rapidly depleted (insulin levels fall, glycogen levels increase)
- FFA liberated, proteins undergo gluconeogenesis
- Body adapts to using FFA/ketones (glucose needs decrease)
- Metabolic rate decreases
- Serum proteins maintained
- Easily reversed with feeds (oral/enteral)
Metabolic Stress/Stress Undernutrition
- > 72 hours
- Cytokines released
- Increased catecholamines, glucocorticoids, GH
- Increased inflammation markers (CRP)
- Insulin resistance associated with hyperglycemia
- Metabolic rate increased
- Accelerated protein catabolism (more nitrogen in urine)
- Not reversed by simply feeding
Malnutrition Key Points
- Nutrition imbalance leads to multiple abnormalities: inadequate intake/increased requirements, impaired absorption, altered nutrient transport and/or utilization
- Patients may present with conditions that are inflammatory, hypercatabolic, and/or hypermetabolic
- Can be caused by long term starvation/undernutrition, chronic diseases, or acute injuries
- Inflammation is important factor for increasing risk of malnutrition
Malnutrition Evaluation
- Energy/nutrition intake - % of energy requirement taken in during last week/month
- Weight loss - % lost over period of time
- Fluid accumulation: generalized or localized
- Loss of body fat
- Loss of muscle mass
Malnutrition Diagnosis
- Severe protein-calorie malnutrition: meets at least 2 criteria from malnutrition criteria table
- Protein-calorie malnutrition: meets 2 criteria from non-severe column OR 1 criteria from severe and 1 from non-severe
Clinical Consequences of Malnutrition
- Decrease immune function: primary decreases in cell-mediated immunity
- Decreased muscle function (skeletal, respiratory, cardiac)
- Decreased wound healing (fistula formation, wound dehiscence, abscess formation, anastomotic breakdown
Fistula Formation
- Abnormal connection that connects two organs/vessels that don’t normally connect
- Complications: significant fluid/electrolyte/minerals/protein loss, dehydration, imbalances, malnutrition
Wound Dehiscence
- Partial or total separation of previously approximated wound edges: failure of proper wound healing
- Clinical significance: poor perfusion, infection risk, malnutrition
- May require another surgery to fix
Physiologic Energy Needs
- Energy required for all metabolic processes, growth, repair, and activity
- Body will utilize its tissue for fuel if energy isn’t provided (catabolism)
- Results in depletion of body cell mass and complications of malnutrition
BMR
- Basal metabolic rate: energy required to maintain body cell mass and basal organ functions
- Estimated with REE (resting energy expenditure) in hospitalized patients
Determining REE
- Predictive Equations: Harris-Benedict (adjusted BW for obese), Mifflin-St. Jeor, Ireton-Hones, Penn State (ventilated patients)
- Indirect Calorimetry (IC) - measure energy expenditure, considered gold standard for hospitalized patients, cost/availability limit use
Harris-Benedict Equation
- REE = BMR * Stress/Activity Factor
- Activity factor varies from Sedentary to Extreme Activity
- Units: kcal/day
Limitations of REE Equation
- No equation is more accurate than IC
- Hundreds of equations posts, all 40-75% accurate
- Even less accurate in obese and underweight patients
- Poor accuracy due to non-static variables (weight, medications, body temp)
Indirect Calorimetry
- Most accurate method of determining REE
- Measures oxygen consumption and CO2 production to calculate whole body energy catabolism over a day
- Variables that effect the timing/accuracy of IC readings
- Costly equipment and requires trained personnel
IC Affecting Variables
- Air leaks or chest tubes
- Supplemental oxygen
- Ventilator settings
- CRRT
- Anesthesia
- PT and/or excessive movement
Weight Based Equations
- Recommend this or REE equation when IC not available
- Non-obese: 25-30 kcal/day (BW)
Obese Patients
- BMI 30-50: 11-14 kcal/kg/day (BW)
- BMI > 50: 22-25 kcal/kg/day (IBW)
IBW
Male:
106 lb for first 60 inches + 6 lbs for each inch > 60 inches
Female:
100 lbs for first 60 inches + 5 lbs each inch > 60 inches
Enteral Nutrition
- EN
- Nutrition provided by feeding tube into GI tract
- Not oral and NOT IV
Physiological EN Benefits
- Supports functional integrity of gut: stimulate blood flow, release of trophic agents, maintains tight junctions
- Maintains structural integrity by maintaining villous height and supporting mass of secretory IgA-producing immunocytes in gut lymphoid tissue
Additional Benefits of EN
- Modulate stress and systemic immune response
- Attenuate disease severity
- Fewer complications compared to PN
- Lower cost compared to PN
Disadvantages of EN
- Aspiration and VAP (higher risk => place postpyloric)
- GI: diarrhea, nausea, vomiting, distension (proper rate of admin, product selection, and goal rate)
- Complications from tube placement
- Stigma of feeding tubes
EN Contraindications
- Small or Large intestinal obstructions
- Paralytic ileus
- Peritonitis
- GI Ischemia
- Relative and constantly changing (growing body of research on EN and outcomes)
EN vs PN
- Selecting appropriate route is key to optimize outcomes
- EN is preferred unless there are contraindications, not tolerate after repeated attempts, unable to meet nutritional goals with EN
- Even if on PN, initiate EN as soon as safely possible
EN Formula Composition
Main components:
- Protein: 15-20% of total calories
- Carbs: 40-60% of total calories
- Lipids: 25-40% of total calories
- Electrolytes: minerals, vitamins, trace elements
-Different formulas available for special conditions (renal, hepatic, stress, diabetes)
Standard Polymeric EN
- Nutrient distribution for normal diet
- Indication: Normal GI fxn
High Protein Polymeric EN
- Protein >15% of total energy
- Indications: Catabolic states, wound healing
Partially Hydrolyzed Oligomeric EN
- “Semi-elemental”
- Composition varies where one or more macro-nutrients are hydrolyzed
- Indications: impaired digestion/absorption, pancreatic insufficiency, IBD
FAA Monomeric EN
- “Elemental”
- Hydrolyzed formula, low residue
- Indication: Crohn’s disease possible, falling out of favor in adults in favor of oligomeric EN
Metabolism in Critically Ill
- Metabolic response to stress is adaptive to survive acute illness - increase energy provision to vital tissues, altered pathways of energy production and alt. substrates needed
- Patients at risk for stress hyperglycemia - high [glucose] increase production and/or expression of pro-inflammatory mediators
Protein in ICU
- Protein loss occurs universally in ICU (less muscle mass)
- Magnitude of protein loss associated with increased morbidity/mortality
- Manifestations of severe protein malnutrition: respiratory failure, immune dysfxn, poor wound healing
- Protein most important nutrient for protecting lean body mass
- Higher protein intake early shown to decrease mortality (opposite in overfeeding)
- *Most important macronutrient, focus on protein if caloric requirement can’t be met**
Enteral Protein Dosing
-Standard goal: 1.2-2 g/kg/day
-Burn patients: 1.5-2 g/kg/day
-CRRT/frequent HD patients: 2.5 g/kg/day (don’t restrict in renal insufficiency)
Obese
-BMI 30-40: 2g/kg/day (IBW)
-BMI >40: up to 2.5 g/kg/day (IBW)
Avoid protein restriction, especially in CRRT and liver failure pts
EN in ICU
- Start within 24-48 hours in critically ill patients who can’t maintain PO intake on their own
- ICU patients at risk for adverse changes in gut permeability
- Could lead to bacterial challenges, risk for systemic infection, increased risk of multiple-organ dysfxn syndrome
- As disease status worsens, increases in gut permeability amplifies and EN more likely to favorably impact those AE
Acute Pancreatitis Considerations
- Mild acute pancreatitis: advance to PO diet as tolerated, consider EN/PN if unable to advance within 7 days
- Mod-Severe: Place NG/OG and start trophic rate, advancing to goal as fluid volume resuscitation completed
- Use polymeric formula when initiating early EN
- EN>PN in severe pancreatitis (except necrotizing pancreatitis), consider adding probiotic
Trauma Surgical Patient Consideration
- Early enteral feedings with high protein polymeric diet initiated within 24-48 hours of injury once stable
- Consider immune-modulating formulas with arginine and fish oil in severe trauma patients
Traumatic Brain Injury Considerations
- Similar to other critically ill patients, initiate early EN within 24-48 hours once stable
- Consider using arginine-containing immune-modulating formulas or EPA/DHA supplement with standard EN formula (may accelerate recovery)
Open Abdomen Considerations
- OA technique, used to manage abdominal contents after damage control laparotomy
- May have OA for days to weeks post-op
- Very pro-inflammatory state
- Initiate early EN 24-48 hours post-op in patients with OA in absence of bowel injury
- Consider adding additional 15-30 g of protein per L of exudate loss for OA patients
Burns Consideration
- EN should be given to those with functioning GI and inadequate PO intake
- Use IC when available to assess energy needs and repeat weekly
- Initiate very early EN - within 4-6 hours of injury if possible
- Protein goal: 1.5-2 g/kg
Severe Sepsis/Septic Shock Considerations
- EN within 24-48 hours of diagnosis, as soon as resuscitation is complete and stable
- Not recommended to use exclusive PN or supplemental PN in conjunction with EN in acute phase
Post-op Major Surgery Considerations
- Determine nutrition risks on all post-of patients in ICU
- Suggest initiating EN when feasible in post-op period within 24 hours of surgery
- Suggest routine use of immune-modulating formula (arginine and fish oils) in SICU for post-ops
Chronically Critically Ill Considerations
- Persistent organ dysfunction requiring ICU stay of >21 days
- Persistent inflammation, immunosuppression, and catabolism syndrome
- Manage patients with aggressive high-protein EN therapy (also resistance exercise program when possible)
Obesity in Critical Illness Patients Differences
- More likely to have fuel utilization issues (greater loss of LBM)
- Greater risk of insulin resistance
- Get higher percentage of energy needs from protein metabolism
- More complication than others with normal BMI: infection, longer stays, more organ failure, longer mechanical ventilation durations
Obesity in ICU Considerations
- EN within 24-48 hours of admission if PO intake can’t be sustained
- High-protein hypocaloric EN to preserve LBM, mobilize adipose tissues, and minimize metabolic complications from overfeeding
- Give supplemental thiamine prior to starting dextrose-containing fluids if history of bariatric surgery
- Evaluate and treat for micronutrient deficiencies in bariatric surgery patients as well